The North American Electric Reliability Corporation (NERC) is a not-for-profit international regulatory authority whose mission is to assure the reliability and security of the bulk power system in North America. NERC develops and enforces Reliability Standards; annually assesses seasonal and long‐term reliability; monitors the bulk power system through system awareness; and educates, trains, and certifies industry personnel. NERC’s area of responsibility spans the continental United States, Canada, and the northern portion of Baja California, Mexico. NERC is the electric reliability organization (ERO) for North America, subject to oversight by the Federal Energy Regulatory Commission (FERC) and governmental authorities in Canada. NERC's jurisdiction includes users, owners, and operators of the bulk power system, which serves more than 334 million people.

This Wide-Area Perspective on the August 21, 2017 Total Solar Eclipse document was created in order to evaluate potential reliability consequences of the total solar eclipse on the BPS. This assessment focuses specifically on impacts of system loading and potential reliability implications when an area experiences a large reduction of distributed energy resource (DER) capacity due to a total solar eclipse. Ramping is a specific concern for areas with large amounts of variable generation in their resource mix. The areas that have ramping issues will need further evaluation by the Regions and include areas that are not in the direct path of the eclipse. An example of such an area is California, where the transmission (utility) installed nameplate capacity for solar generation is 11,444 MW. Some areas in Northern California are projected to experience up to 95 percent of the obscuration of the Sun from the August 21, 2017 eclipse.

Understanding the relation between changes to an area’s demand needs, and available generating capacity is traditionally performed through a planning reserve margin analysis. Generally, this analysis compares the forecasted peak load to the amount of capacity that could be considered available to serve peak load. Included in these values are considerations for passive or controllable peak load reduction programs, also referred to as DSM. When compared to an individual area’s target reserve margin level (or Reference Margin Level), this deterministic-based calculation provides a straightforward viewpoint on the adequacy of a system’s resources for all ten years of the assessment.